Development Of A New SERS Substrate And Analytical Detection Of Crystalline Violet And Manganese Ions Research

With the continuous socio-economic development,industrial pollution has become an inescapable problem in the water environment.Pollutants have posed a great threat to ecology and human health.At the same time,rapid and simple detection of pollutants in the environment has placed greater demands on the supervisory and testing authorities.Surface Enhanced Raman Scattering（SERS）is a highly sensitive spectroscopic detection technique developed in recent years,which has the advantages of rapid,simple and trace detection and shows great promise in the detection of pollutants in the water environment.In this paper,two Raman substrates were prepared by selecting crystalline violet and manganese ions as the objects of detection and analysis.The main research of this thesis includes:（1）A new SERS substrate of CTS-Ag with good stability,easy preparation,high Raman intensity and easy storage was fabricated using ethylene glycol reduced silver nitrate.The surface structure of the material was observed using scanning electron microscopy（SEM）.The artificial dye rhodamine B（R6G）was selected as the probe molecule to detect the SERS enhancement efficacy of this substrate.The detection of polyalkylated aromatic crystalline violet（CV）was performed using CTS-Ag composite substrate,and the signal of the characteristic peak of crystalline violet was well enhanced and good linearity was obtained in the range of 1×10^-10-1×10^-5 mol/L.This study provides a new method for the development of the SERS technique.On this basis,the CTS-Ag substrate was applied to the quantitative detection of crystalline violet in real water and fish.（2）The SERS probe was constructed as a hybrid system containing silver nanoparticles（Ag NPs）,6-mercaptonicotinic acid（MNA）and melamine（MA）.The possible principle of this SERS probe for the analysis of manganese ions(Mn²⁺)is that 6-mercaptonicotinic acid cooperates with melamine to bind manganese ions leading to aggregation of silver nanoparticles,which rapidly enhances the Raman signature signal of 6-mercaptonicotinic acid.This aggregation effect caused by heavy metals will be tested by ultraviolet-visible（UV-vis）and transmission electron microscopy（TEM）.The MNA-MA-Ag NPs probe achieves good linearity and selectivity in the range of 1.0×10^-5-1.0×10^-4 mol/L for the detection of manganese ions by optimising the parameters such as modifier ratio and pH value.On this basis,it was applied to the detection of manganese ions in drinking water.